Basement Wall Design Span

[NateB]

When designing a basement wall with at-rest earth pressure, what design span is typically used?

Top of SLAB ON GRADE (or sometimes just grade) to brace point above

or

Top of FOOTING to brace point above.

I have used the top of footing for design of flexural reinforcement, but then considered the slab on grade (or grade) to brace against sliding. When the slab on grade is "floating" there is no positive contact, this is a very typical condition encountered by our office.

Any comments on your standard design methods are appreciated.

Thanks.

 

[jike]

I would use the top of footing to figure the wall bending moment. Any slight rotation of the wall will unlikely be resisted by the slab. If the slab on grade is used to prevent sliding, pour slab tight to wall with no exp. jt. material.